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Multiple components of membrane retrieval in synaptic terminals revealed by changes in hydrostatic pressure
Ruth Heidelberger1, Zhen-Yu Zhou, Gary Matthews
1Department of Neurobiology, The W. M. Keck Center for the Neurobiology of Learning and Memory, University of Texas Medical School, Houston, Texas 77030, USA. ruth.heidelberger@uth.tmc.edu
Journal of Neurophysiology
|November 9, 2002
Summary
Hydrostatic pressure reversibly inhibits compensatory endocytosis in synaptic terminals. This finding suggests distinct mechanisms regulate membrane retrieval, crucial for synaptic function.
Area of Science:
- Neuroscience
- Cell Biology
Background:
- Membrane retrieval after exocytosis (synaptic vesicle recycling) is essential for sustained neuronal activity.
- The specific factors regulating this compensatory endocytosis remain largely unknown.
Purpose of the Study:
- To investigate the impact of hydrostatic pressure on compensatory endocytosis in retinal bipolar neuron synaptic terminals.
- To elucidate the mechanisms underlying membrane retrieval following exocytosis.
Main Methods:
- Whole-terminal capacitance measurements were employed to monitor membrane dynamics.
- Single synaptic terminals of retinal bipolar neurons were utilized for experiments.
Main Results:
- A modest increase in hydrostatic pressure reversibly inhibited compensatory endocytosis.
- A fast endocytic component persisted, while a slower component was inhibited under pressure.
- A slower endocytosis mechanism restored resting membrane capacitance upon pressure release.
Conclusions:
- Hydrostatic pressure significantly impacts membrane retrieval, suggesting its careful control during endocytosis studies.
- At least two distinct mechanisms contribute to compensatory endocytosis.
- Presynaptic surface area is tightly regulated, even when endocytosis is uncoupled from exocytosis.